The disclosure relates to a hydraulic valve arrangement, for example for controlling the pressure and volumetric flow of an axial piston machine.
A hydraulic valve arrangement of this type is known from DE 10 2010 048 068 A1 and has a valve housing, in which a pressure control valve and a delivery-flow control valve of an axial piston pump are arranged in an axially parallel manner. Each of said control valves has a valve body which is guided in a valve bore and via which a pressure medium connection between a pressure connector which is loaded with the pump pressure (system pressure) and a tank connector or a control connector can be opened and closed, with the result that a pressure space of an actuating cylinder is loaded correspondingly with the system pressure or the tank pressure. The valve bodies of the delivery-flow control valve and the pressure control valve are loaded in each case via a control spring in a direction, in which the pressure space is connected to the tank and the pressure medium connection between the control connector and the pressure connector which conducts the system pressure is shut off. The control behavior of the two control valves can be set by setting and adjusting of the spring prestress of the two control springs.
In the known solution, each control spring is supported indirectly or directly on a setting screw which is in threaded engagement with the valve housing, with the result that the spring prestress can be varied by screwing in or screwing out the setting screw. The adjustment is performed at the factory, the setting screw then being braced with a lock nut in order to fix the preset value. Both the head of the setting screw and the lock nut are configured with a hexagon socket, the hexagon socket on the lock-nut side being configured as a passage opening, through which the tool for adjusting the setting screw can be attached. Both the head of the setting screw and the lock nut are arranged countersunk in a receiving bore of the housing, with the result that accidental adjustment is made more difficult.
DE 10 2010 048 068 A1 which is mentioned above and DE 10 2009 052 076 A1 disclose a solution, in which the spring seat is not configured as a setting screw, but rather is configured by an expander. An expander of this type has an expanding sleeve, into which an expanding element is inserted, by way of the axial displacement of which the expanding sleeve is calked to the housing or the like.
All these solutions have the common disadvantage that a comparatively large number of structural elements are required, in order to set the spring prestress and to secure the spring seat against adjustment.
A further disadvantage consists in that the valve arrangement has to be configured with a correspondingly larger overall length as a result of the required structural elements, for example the setting screw and the lock nut or the expander.
In contrast, the disclosure is based on the object of providing a valve arrangement, in which the spring prestress can be set and fixed with low outlay, a small amount of installation space and few parts.